1. Field of the Invention
The present invention relates generally co an apparatus for cutting predetermined lengths of a flexible material such as thread, rope, wire, tubing, and the like, and more specifically, to an apparatus for automatically cutting a predetermined length of suture material for attachment to a surgical needle. More particularly, the present invention relates to apparatus for cutting an indefinite length of suture to different discrete lengths for subsequent swaging to surgical needles, and having a tipping assembly. The tipping assembly heats a predetermined small length of the suture to stiffen it in preparation for cutting the stiffened suture at a cutting assembly and inserting a stiffened lead cut end of the suture into an end of a needle for swaging thereto. A long length of suture travel is provided between the tipping assembly and the cutter assembly which is a discrete number of apparatus cutting cycles between the tipping and cutting operations to allow the tipped suture to cool prior to cutting.
2. Description of the Prior Art
The medical products industry presently utilizes semi-automated procedures for swaging sutures to surgical needles. For instance, as described in U.S. Pat. No. 3,611,551, manual intervention is required by an operator to accurately position a suture within the needle for swaging and to adjust swaging dies to increase or decrease swage pressure when suture strands of different gauges are to be swaged. This process is costly in terms of man-hour labor and efficiency because manual positioning is required for swaging to take place.
Presently, suture material may be supplied wound on a bobbin, or, a king or driven spool before being cut and positioned within the swaging end of a surgical needle. In U.S. Pat. No. 3,980,177 the suture material is fed from a spool and taken up on a rotating tension rack where uniform length strands are subsequently cut. Thus, the length of the suture is determined by the size of the rack and manual intervention is required to change the rack each time a different length of suture is desired.
In U.S. Pat. No. 4,922,904, the suture material is supplied wound on a bobbin and is fed through various guide means and a heater for straightening the material, prior to insertion within the crimping cavity of the surgical needle. In one embodiment shown therein, an elaborate television monitoring means is required for aligning the drawn suture within the crimping cavity of the surgical needle prior to swaging thereof. In the same embodiment, a rotary encoder device is used to determine the length of suture material unwound from the bobbin prior to cutting. In an alternative embodiment, after swaging of the indefinite length of suture material to the needle, the needle-suture assembly is additionally fed a predetermined distance prior to cutting to obtain a suture strand of predetermined length. Thus, to obtain uniform lengths of suture material every time requires careful manipulations and precise controls, and the processes used to accomplish these tasks are also costly in terms of man-hour labor and efficiency.
It would be far more desirable to provide a suture cutting system and apparatus that is fully automated and which can automatically cut uniform lengths of suture material at high-speeds.
It would also be highly desirable to provide a suture cutting system that can accurately position suture material within the confines of the crimping ends of surgical needles at an appreciable rate and without elaborate techniques or manual procedures.
It would also be desirable to provide a suture cutting system which is operable under the control of a control system computer, and which that can provide automatic adjustments to the swage tooling dies when different size sutures are swaged in to various sized surgical needles.